Gen 8.6 Comm. Bridge crashes for high number of connections
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Gen 8.6 Comm. Bridge crashes for high number of connections


Article ID: 135284


Updated On:


Gen Gen - Host Encyclopedia Gen - Run Time Distributed Gen - Workstation Toolset


After upgrade to Gen 8.6 the Communications Bridge/Comm. Bridge (CB) crashes during a stress test for a large number of connections.


Release: 8.6
Component: Gen Communications Bridge


In Gen 8.5 the maximum size of the Common Format Buffer (CFB) used for Gen client/server view data transport was increased from 32 KB to 16 MB (Gen™ 8.5 > Release Notes > CA Gen Release 8.5 > Remove 32 KB CFB Limit) and 16 MB became the default memory allocated per Comm. Bridge connection.
In Gen 8.6  the default memory allocated per Comm. Bridge connection is also 16 MB.


If the large CFB feature is not required to be used Gen 8.5 Comm. Bridge PTFs CCN85001/RO68926 & CCN85003/RO79154 provide a method to set a Windows System environment variable to enable each connection to have the previous lower maximum CFB value of 32 KB. The same method is available in Gen 8.6 GA and later versions.
Set Windows System environment variable VIEWSIZE32K=1 and restart the Comm. Bridge service.

If the large CFB feature is required to be used then either the number of connections per Comm. Bridge server needs to be limited or the available memory needs to be increased.

Additional Information

It has been reported by one customer that in very old Gen 8.5 Comm. Bridge tests (probably prior to memory fixes) problems had been encountered with exceeding just 100 connections.
That same customer ran a simulation of 150 looping connections/test (echo) transactions through the Gen 8.6 Comm. Bridge to a Gen server and the Comm. Bridge service crashed with iefcbn.exe reporting an exception in file C:\Windows\System32\ucrtbase.dll. The crash was resolved by adding SYSTEM level environment variable VIEWSIZE32K=1.